Coal or rock drill.



No. 721,896. PATENTED MAR. 3, 1903.

L. K. KOONTIZ. GOAL 0R ROGK'DRILL.

PPLIOATION FILED MAE. 7, 1901.

W I f v. l3?

UNITED STATES PATENT OFFICEQ LOUIS K. KOONTZ, OF ALLEGHENY,PENNSYLVANIA, ASSIGNOR TO MARTIN HARDSOOG MANUFACTURING COMPANY,LIMITED, OF ALLEGHENY,

PENNSYLVANIA COAL OR ROCK DRILL.

$PECIFIGATION forming part of Letters Patent No. 721,896, dated March 3,1903.

Application filed March '7, 1901.

T (ZZZ whom it may concern:

Be it known that I, LOUIS K. KOONTZ, a citizen of the UnitedStates,residingat Allegheny, in the county of Allegheny and State ofPennsylvania, have invented new and useful Improvements in Goa] or BookDrills, of which the following is a specification. V

This invention relates to improvements in coal and rock drills, and hasparticular refer- IO ence to an improved reversible andautomatically-variable feed mechanism for controlling the advance of thedrill or anger.

The invention consists in the novel structural features and combinationand arrangement of parts hereinafter fully described and claimed,andillustrated by the accompanying drawings, wherein Figure 1 is a verticallongitudinal sectional view of my improved mechanism shown in positionon a drill. Fig. 2 is a rear elevation of the same with the face-plateor collar removed and the feed-bar shown in section. Fig. 3 is anenlarged longitudinal sectional View of the improved mechanism. Fig. 4is a detail view of the spring.

Referring to the drawings, 2 represents the twist-drill, 3 the feed-bar,4 the crank, 5 the forked chair, and 6 the chair-supporting gripbar, allof usual and well-known construction.

7 is a bearing-head provided with side trunnions 8, which rest in thearms of chair 5. Head 8 is formed with a central circular opening toreceive the internally-threaded nut or sleeve 9, and one side face ofthe head is coun- 5 tersunk at 10 to receive annular shoulder 11 of saidnut. The depression and shoulder are of the same depth, and the latteris confined in the former by the annular plate or collar 12, secured tohead 7 by bolts 13. Thus the 0 nut or sleeve is rotatably confined inthe head 7, while the threaded feed-bar works through the nut, as willbe understood. Head 7 is reversible in that either face thereof may bedisposed toward the coal.

For retarding the rotation of nut 9 in head 7 the upper portion ofcountersunk depression 10 is enlarged at 14, and intersecting the centerof this enlargement is a threaded aperture through which Works theset-screw l5, and within the enlargement and arranged cen- Serial No.50.187. (No model.)

trally beneath this screw is the bowed spring 16, the extremities ofwhich bear on the periphery of nut-shoulder 11. Thus the spring has abroad bearing-surface on the nut and, if necessary,may be forced down tobear thereagainst its whole length.

In operation if the resistance of the anger is sufficient to overcomethe resistance of spring 16 nut 9 will rotate with the feed-bar. Hencethe drill and not will simply rotate Within head 7. On the other hand,if the tension of the spring is sufficient to hold not 9 stationary,notwithstanding the resistance of the drill, the feed-bar will advancetherethrough. Under ordinary working conditions the adjustment by meansof screw 15 is such that the opposing resistances are about evenlybalanced, with the result that nut 9 rotates, but at a slower speed thanthe feedbar and drill. However, this may be arranged as circumstancesmay requi1'e-as, for instance, if Working in comparatively soft materialand a rapid feed is desirable the tension of the spring 15 may be soincreased as to hold the nut fixed, thus creating a positive feed forthe bar working therethrough.

It will of course be understood that instead of the chair and barsupport a vertical post may be substituted and that a ratchet-lever maybe substituted for crank 4.

Having thus fully described myinvention, what I claim as new, and desireto secure by Letters Patent, is-

1. The combination of a fixed head, a feednut rotatable therein, a bowedspring-normally of sharper curvature than the nutconfined by the headand disposed transversely of the nut-axis and adapted at its ends tobear on the nut periphery, and means operating on the spring forcompressing the same against the nut, thereby increasing the pressure ofthe spring on the nut and increasing its frictional engagementtherewith.

2. The combination of non-rotating head 7 formed with a circular openingcountersunk 95 at 10, internally-threaded nut 9 formed with annularexternal shoulder 11 corresponding to and fitting within the countersunkportion of the head-opening, plate 12 formed with an annular opening toembrace the nut In testimony whereof I have hereunto set my hand inpresence of two subscribing wit- :0 nesses.

LOUIS K. KOONTZ.

Witnesses:

J. M. NESBIT, ALEX. S. MABON.

